Systems and methods for initial assessment warnings

ABSTRACT

A surgical system includes a first trackable marker configured to be coupled to a first bone of a joint, a second trackable marker configured to be coupled to a second bone of the joint, and a tracking system configured to track a position of the first trackable marker and a position of the second trackable marker. A controller is configured to receive an input from a user specifying a user-input native deformity of the joint and determine, based on the position of the first trackable marker and the position of the second trackable marker, a detected native deformity of the joint. The controller is further configured to compare the detected native deformity of the joint to the user-input native deformity of the joint and generate an alert in response to a disagreement between the detected native deformity of the joint and the user-input native deformity of the joint.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of and priority to U.S. ProvisionalPatent Application No. 63/125,468 filed Dec. 15, 2020, U.S. ProvisionalPatent Application No. 63/177,034 filed Apr. 20, 2021, and U.S.Provisional Patent Application No. 63/226,858 filed Jul. 29, 2021, theentire disclosures of which are incorporated by reference herein.

BACKGROUND

The present disclosure relates generally to surgical systems fororthopedic surgeries, for example surgical systems that facilitate jointreplacement procedures. Joint replacement procedures (arthroplastyprocedures) are widely used to treat osteoarthritis and other damage toa patient's joint by replacing portions of the joint with prostheticcomponents. Joint replacement procedures can include procedures toreplace hips, knees, shoulders, or other joints with one or moreprosthetic components.

One possible tool for use in an arthroplasty procedure is arobotically-assisted surgical system. A robotically-assisted surgicalsystem typically includes a robotic device that is used to prepare apatient's anatomy to receive an implant, a tracking system configured tomonitor the location of the robotic device relative to the patient'sanatomy, and a computing system configured to monitor and control therobotic device. Robotically-assisted surgical systems, in various forms,autonomously carry out surgical tasks, provide force feedback to a usermanipulating a surgical device to complete surgical tasks, augmentsurgeon dexterity and precision, and/or provide other navigational cuesto facilitate safe and accurate surgical operations.

A surgical plan is typically established prior to performing a surgicalprocedure with a robotically-assisted surgical system. Based on thesurgical plan, the surgical system guides, controls, or limits movementsof the surgical tool during portions of the surgical procedure. Guidanceand/or control of the surgical tool serves to assist the surgeon duringimplementation of the surgical plan. Various features enabling improvedplanning, improved intra-operative assessments of the patientbiomechanics, intraoperative plan adjustments, etc. for use withrobotically-assisted surgical systems or other computer-assistedsurgical systems may be advantageous.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a femur prepared to receive an implantcomponent, according to an exemplary embodiment.

FIG. 2 is an illustration of a surgical system, according to anexemplary embodiment.

FIG. 3 is a flowchart of a first process that can be executed by thesurgical system of FIG. 2, according to an exemplary embodiment.

FIG. 4 is a flowchart of a second process that can be executed by thesurgical system of FIG. 2, according to an exemplary embodiment.

FIG. 5 is an illustration of a graphical user interface showing arelationship between a virtual femur and a virtual tibia, according toan exemplary embodiment.

FIG. 6 is another illustration of the graphical user interface of FIG. 5showing another relationship between the virtual femur and the virtualtibia, according to an exemplary embodiment.

FIG. 7 is yet another illustration of the graphical user interface ofFIG. 5 showing another relationship between the virtual femur and thevirtual tibia, according to an exemplary embodiment.

FIG. 8 is a flowchart of a process to determine a native deformity of ajoint, according to an exemplary embodiment.

SUMMARY

A surgical system includes a first trackable marker configured to becoupled to a first bone of a joint, a second trackable marker configuredto be coupled to a second bone of the joint, and a tracking systemconfigured to track a position of the first trackable marker and aposition of the second trackable marker. A controller is configured toreceive an input from a user specifying a user-input native deformity ofthe joint and determine, based on the position of the first trackablemarker and the position of the second trackable marker, a detectednative deformity of the joint. The controller is further configured tocompare the detected native deformity of the joint to the user-inputnative deformity of the joint and generate an alert in response to adisagreement between the detective native deformity of the joint and theuser-input native deformity of the joint.

In some implementations, the controller is further configured togenerate the alert when the detected native deformity differs from theuser-input deformity by more than a threshold amount.

In some implementations, the controller is further configured to promptthe user to take action to correct an error that caused the disagreementbetween the detected native deformity and the user-input nativedeformity. The controller is further configured to receive an updateduser-input native deformity, and compare the updated user-input nativedeformity to the detected native deformity.

In some implementations, the controller is further configured to promptthe user to take action to correct an error that caused the disagreementbetween the detected native deformity and the user-input nativedeformity. The controller is further configured to determine an updateddetected native deformity, and compare the updated detected nativedeformity to the user-input native deformity.

In some implementations, the alert includes one or more of a visualalert displayed on a graphical user interface and an audible alertprovided through an audible device.

In some implementations, a graphical user interface is configured todisplay the detected native deformity and show a virtual representationof the first bone and a virtual representation of the second bone.

In some implementations, the graphical user interface is furtherconfigured to display the detected native deformity based on anatomicallandmarks of the virtual representation of the first bone and thevirtual representation of the second bone.

A method of providing surgical navigation includes tracking a positionof a first trackable marker coupled to a first bone of a joint andtracking a position of a second trackable marker coupled to a secondbone of the joint. The method further includes receiving an input from auser specifying a user-input native deformity of the joint anddetermining, based on the position of the first trackable marker and theposition of the second trackable marker, a detected native deformity ofthe joint. The method further includes comparing the detected nativedeformity of the joint to the user-input native deformity of the jointand generating an alert in response to a disagreement between thedetected native deformity of the joint and the user-input nativedeformity of the joint.

In some implementations, the method includes generating the alert whenthe detected native deformity differs from the user-input deformity bymore than a threshold amount.

In some implementations, the method further includes prompting the userto take action to correct an error that caused the disagreement betweenthe detected native deformity of the joint and the user-input nativedeformity of the joint. The method further includes receiving an updateduser-input native deformity, and comparing the updated user-input nativedeformity to the detected native deformity.

In some implementations, the method further includes prompting the userto take action to correct an error that caused the disagreement betweenthe detected native deformity of the joint and the user-input nativedeformity of the joint. The method further includes determining anupdated detected native deformity, and comparing the updated detectednative deformity to the user-input native deformity.

In some implementations, the alert includes one or more of a visualalert displayed on a graphical user interface and an audible alertprovided through an audible device.

In some implementations, the method further includes displaying thedetected native deformity on a graphical user interface and showing avirtual representation of the first bone and a virtual representation ofthe second bone.

In some implementations, the method further includes displaying thedetected native deformity on the graphical user interface by showinganatomical landmarks of the virtual representation of the first bone andthe virtual representation of the second bone.

A navigation system includes a computer programmed to track a positionof a first trackable marker coupled to a first bone of a joint and tracka position of a second trackable marker coupled to a second bone of thejoint. The computer is further programmed to receive an input from auser specifying a user-input native deformity of the joint anddetermine, based on the position of the first trackable marker and theposition of the second trackable marker, a detected native deformity ofthe joint. The computer is further programmed to compare the detectednative deformity of the joint to the user-input native deformity of thejoint.

In some implementations, the computer is further programmed to generatean alert in response to determining a disagreement between the detectednative deformity and the user-input native deformity.

In some implementations, the computer is further programmed to promptthe user to take action to correct an error that caused the disagreementbetween the detected native deformity and the user-input nativedeformity. The computer is further programmed to receive an updateduser-input native deformity, and compare the updated user-input nativedeformity to the detected native deformity.

In some implementations, the computer is further programmed to promptthe user to take action to correct an error that caused the disagreementbetween the detected native deformity and the user-input nativedeformity. The computer is further programmed to determine an updateddetected native deformity, and compare the updated detected nativedeformity to the user-input native deformity.

In some implementations, the computer is further programmed to displaythe detected native deformity on a graphical user interface and show avirtual representation of the first bone and a virtual representation ofthe second bone.

In some implementations, the computer is further programmed to displaythe detected native deformity on the graphical user interface based onanatomical landmarks of the virtual representation of the first bone andthe virtual representation of the second bone.

DETAILED DESCRIPTION

Presently preferred embodiments of the invention are illustrated in thedrawings. An effort has been made to use the same or like referencenumbers throughout the drawings to refer to the same or like parts.Although this specification refers primarily to a robotic arm fororthopedic joint replacement, it should be understood that the subjectmatter described herein is applicable to other types of robotic systems,including those used for non-surgical applications, as well as forprocedures directed to other anatomical regions, for example spinal ordental procedures.

Referring now to FIG. 1, a femur 101 as modified during a kneearthroplasty procedure is shown, according to an exemplary embodiment.As shown in FIG. 1, the femur 101 has been modified with multiple planarcuts. In the example shown, the femur 100 has been modified by fivesubstantially planar cuts to create five substantially planar surfaces,namely distal surface 102, posterior chamfer surface 104, posteriorsurface 106, anterior surface 108, and anterior chamfer surface 110. Theplanar surfaces may be achieved using a sagittal saw or other surgicaltool, for example a surgical tool coupled to a robotic device as in theexamples described below. The planar surfaces 102-110 are created suchthat the planar surfaces 102-110 will mate with corresponding surfacesof a femoral implant component. The positions and angular orientationsof the planar surfaces 102-110 may determine the alignment andpositioning of the implant component. Accordingly, operating a surgicaltool to create the planar surfaces 102-110 with a high degree ofaccuracy may improve the outcome of a joint replacement procedure.

As shown in FIG. 1, the femur 101 has also been modified to have a pairof pilot holes 120. The pilot holes 120 extend into the femur 101 andare created such that the pilot holes 120 can receive a screw, aprojection extending from a surface of an implant component, or otherstructure configured to facilitate coupling of an implant component tothe femur 101. The pilot holes 120 may be created using a drill,spherical burr, or other surgical tool as described below. The pilotholes 120 may have a pre-planned position, orientation, and depth, whichfacilitates secure coupling of the implant component to the bone in adesired position and orientation. In some cases, the pilot holes 120 areplanned to intersect with higher-density areas of a bone and/or to avoidother implant components and/or sensitive anatomical features.Accordingly, operating a surgical tool to create the pilot holes 120with a high degree of accuracy may improve the outcome of a jointreplacement procedure.

A tibia may also be modified during a joint replacement procedure. Forexample, a planar surface may be created on the tibia at the knee jointto prepare the tibia to mate with a tibial implant component. In someembodiments, one or more pilot holes or other recess (e.g., fin-shapedrecess) may also be created in the tibia to facilitate secure couplingof an implant component tot eh bone.

In some embodiments, the systems and methods described herein providerobotic assistance for creating the planar surfaces 102-110 and thepilot holes 120 at the femur, and/or a planar surface and/or pilot holes120 or other recess on a tibia. It should be understood that thecreation of five planar cuts and two cylindrical pilot holes as shown inFIG. 1 is an example only, and that the systems and methods describedherein may be adapted to plan and facilitate creation of any number ofplanar or non-planar cuts, any number of pilot holes, any combinationthereof, etc., for preparation of any bone and/or joint in variousembodiments. For example, in a hip or shoulder arthroplasty procedure, aspherical burr may be used in accordance with the systems and methodsherein to ream a curved surface configured to receive a curved implantcup. Furthermore, in other embodiments, the systems and methodsdescribed herein may be used to facilitate placement an implantcomponent relative to a bone (e.g., to facilitate impaction of cupimplant in a hip arthroplasty procedure). Many such surgical andnon-surgical implementations are within the scope of the presentdisclosure.

The positions and orientations of the planar surfaces 102-110, pilotholes 120, and any other surfaces or recesses created on bones of theknee joint can affect how well implant components mate to the bone aswell as the resulting biomechanics for the patient after completion ofthe surgery. Tension on soft tissue can also be affected. Accordingly,systems and methods for planning the cuts which create these surfaces,facilitating intra-operative adjustments to the surgical plan, andproviding robotic-assistance or other guidance for facilitating accuratecreation of the planar surfaces 102-110, other surfaces, pilot holes120, or other recesses can make surgical procedures easier and moreefficient for healthcare providers and improve surgical outcomes.

Referring now to FIG. 2, a surgical system 200 for orthopedic surgery isshown, according to an exemplary embodiment. In general, the surgicalsystem 200 is configured to facilitate the planning and execution of asurgical plan, for example to facilitate a joint-related procedure. Asshown in FIG. 2, the surgical system 200 is set up to treat a leg 202 ofa patient 204 sitting or lying on table 205. In the illustration shownin FIG. 2, the leg 202 includes femur 206 (e.g., femur 101 of FIG. 1)and tibia 208, between which a prosthetic knee implant is to beimplanted in a total knee arthroscopy procedure. In other scenarios, thesurgical system 200 is set up to treat a hip of a patient, i.e., thefemur and the pelvis of the patient. Additionally, in still otherscenarios, the surgical system 200 is set up to treat a shoulder of apatient, i.e., to facilitate replacement and/or augmentation ofcomponents of a shoulder joint (e.g., to facilitate placement of ahumeral component, a glenoid component, and a graft or implant augment).Various other anatomical regions and procedures are also possible.

The robotic device 220 is configured to modify a patient's anatomy(e.g., femur 206 of patient 204) under the control of the computingsystem 224. One embodiment of the robotic device 220 is a haptic device.“Haptic” refers to a sense of touch, and the field of haptics relatesto, among other things, human interactive devices that provide feedbackto an operator. Feedback may include tactile sensations such as, forexample, vibration. Feedback may also include providing force to a user,such as a positive force or a resistance to movement. One use of hapticsis to provide a user of the device with guidance or limits formanipulation of that device. For example, a haptic device may be coupledto a surgical tool, which can be manipulated by a surgeon to perform asurgical procedure. The surgeon's manipulation of the surgical tool canbe guided or limited through the use of haptics to provide feedback tothe surgeon during manipulation of the surgical tool.

Another embodiment of the robotic device 220 is an autonomous orsemi-autonomous robot. “Autonomous” refers to a robotic device's abilityto act independently or semi-independently of human control by gatheringinformation about its situation, determining a course of action, andautomatically carrying out that course of action. For example, in suchan embodiment, the robotic device 220, in communication with thetracking system 222 and the computing system 224, may autonomouslycomplete the series of femoral cuts mentioned above without direct humanintervention.

The robotic device 220 includes a base 230, a robotic arm 232, and asurgical tool 234, and is communicably coupled to the computing system224 and the tracking system 222. The base 230 provides a moveablefoundation for the robotic arm 232, allowing the robotic arm 232 and thesurgical tool 234 to be repositioned as needed relative to the patient204 and the table 205. The base 230 may also contain power systems,computing elements, motors, and other electronic or mechanical systemnecessary for the functions of the robotic arm 232 and the surgical tool234 described below.

The robotic arm 232 is configured to support the surgical tool 234 andprovide a force as instructed by the computing system 224. In someembodiments, the robotic arm 232 allows a user to manipulate thesurgical tool and provides force feedback to the user. In such anembodiment, the robotic arm 232 includes joints 236 and mount 238 thatinclude motors, actuators, or other mechanisms configured to allow auser to freely translate and rotate the robotic arm 232 and surgicaltool 234 through allowable poses while providing force feedback toconstrain or prevent some movements of the robotic arm 232 and surgicaltool 234 as instructed by computing system 224. As described in detailbelow, the robotic arm 232 thereby allows a surgeon to have full controlover the surgical tool 234 within a control object while providing forcefeedback along a boundary of that object (e.g., a vibration, a forcepreventing or resisting penetration of the boundary). In someembodiments, the robotic arm is configured to move the surgical tool toa new pose automatically without direct user manipulation, as instructedby computing system 224, in order to position the robotic arm as neededand/or complete certain surgical tasks, including, for example, cuts ina femur 206.

The surgical tool 234 is configured to cut, burr, grind, drill,partially resect, reshape, and/or otherwise modify a bone. The surgicaltool 234 may be any suitable tool, and may be one of multiple toolsinterchangeably connectable to robotic device 220. For example, as shownin FIG. 2 the surgical tool 234 includes a spherical burr 244. In otherexamples, the surgical tool may also be a sagittal saw, for example witha blade aligned parallel with a tool axis or perpendicular to the toolaxis. The surgical tool may also be a drill, for example with a rotarybit aligned parallel with a tool axis or perpendicular to the tool axis.The surgical tool 234 may also be a holding arm or other supportconfigured to hold an implant component (e.g., cup 28 a, implantaugment, etc.) in position while the implant component is screwed to abone, adhered (e.g., cemented) to a bone or other implant component, orotherwise installed in a preferred position. In some embodiments, thesurgical tool 234 is an impaction tool configured to provide animpaction force to a cup implant to facilitate fixation of the cupimplant to a pelvis in a planned location and orientation.

Tracking system 222 is configured track the patient's anatomy (e.g.,femur 206 and tibia 208) and the robotic device 220 (i.e., surgical tool234 and/or robotic arm 232) to enable control of the surgical tool 234coupled to the robotic arm 232, to determine a position and orientationof modifications or other results made by the surgical tool 234, andallow a user to visualize the bones (e.g., femur 206, the tibia 208,pelvis, humerus, scapula, etc. as applicable in various procedures), thesurgical tool 234, and/or the robotic arm 232 on a display of thecomputing system 224. The tracking system 222 can also be used tocollect biomechanical measurements relating to the patient's anatomy,assess joint gap distances, identify a hip center point, assess nativeor corrected joint deformities, or otherwise collect informationrelating to the relative poses of anatomical features. Moreparticularly, the tracking system 222 determines a position andorientation (i.e., pose) of objects (e.g., surgical tool 234, femur 206)with respect to a coordinate frame of reference and tracks (i.e.,continuously determines) the pose of the objects during a surgicalprocedure. According to various embodiments, the tracking system 222 maybe any type of navigation system, including a non-mechanical trackingsystem (e.g., an optical tracking system), a mechanical tracking system(e.g., tracking based on measuring the relative angles of joints 236 ofthe robotic arm 232), or any combination of non-mechanical andmechanical tracking systems.

In the embodiment shown in FIG. 2, the tracking system 222 includes anoptical tracking system. Accordingly, tracking system 222 includes afirst fiducial tree 240 coupled to the tibia 208, a second fiducial tree241 coupled to the femur 206, a third fiducial tree 242 coupled to thebase 230, one or more fiducials coupled to surgical tool 234, and adetection device 246 configured to detect the three-dimensional positionof fiducials (i.e., markers on fiducial trees 240-242). Fiducial trees240, 241 may be coupled to other bones as suitable for variousprocedures (e.g., pelvis and femur in a hip arthroplasty procedure).Detection device 246 may be an optical detector such as a camera orinfrared sensor. The fiducial trees 240-242 include fiducials, which aremarkers configured to show up clearly to the optical detector and/or beeasily detectable by an image processing system using data from theoptical detector, for example by being highly reflective of infraredradiation (e.g., emitted by an element of tracking system 222). Astereoscopic arrangement of cameras on detection device 246 allows theposition of each fiducial to be determined in 3D-space through atriangulation approach. Each fiducial has a geometric relationship to acorresponding object, such that tracking of the fiducials allows for thetracking of the object (e.g., tracking the second fiducial tree 241allows the tracking system 222 to track the femur 206), and the trackingsystem 222 may be configured to carry out a registration process todetermine or verify this geometric relationship. Unique arrangements ofthe fiducials in the fiducial trees 240-242 (i.e., the fiducials in thefirst fiducial tree 240 are arranged in a different geometry thanfiducials in the second fiducial tree 241) allows for distinguishing thefiducial trees, and therefore the objects being tracked, from oneanother.

Using the tracking system 222 of FIG. 2 or some other approach tosurgical navigation and tracking, the surgical system 200 can determinethe position of the surgical tool 234 relative to a patient's anatomicalfeature, for example femur 206, as the surgical tool 234 is used tomodify the anatomical feature or otherwise facilitate the surgicalprocedure. Additionally, using the tracking system 222 of FIG. 2 or someother approach to surgical navigation and tracking, the surgical system200 can determine the relative poses of the tracked bones.

The computing system 224 is configured to create a surgical plan,control the robotic device 220 in accordance with the surgical plan tomake one or more bone modifications and/or facilitate implantation ofone or more prosthetic components. Accordingly, the computing system 224is communicably coupled to the tracking system 222 and the roboticdevice 220 to facilitate electronic communication between the roboticdevice 220, the tracking system 222, and the computing system 224.Further, the computing system 224 may be connected to a network toreceive information related to a patient's medical history or otherpatient profile information, medical imaging, surgical plans, surgicalprocedures, and to perform various functions related to performance ofsurgical procedures, for example by accessing an electronic healthrecords system. Computing system 224 includes processing circuit 260 andinput/output device 262.

The input/output device 262 is configured to receive user input anddisplay output as needed for the functions and processes describedherein. As shown in FIG. 2, input/output device 262 includes a display264 and a keyboard 266. The display 264 is configured to displaygraphical user interfaces generated by the processing circuit 260 thatinclude, for example, information about surgical plans, medical imaging,settings and other options for surgical system 200, status informationrelating to the tracking system 222 and the robotic device 220, andtracking visualizations based on data supplied by tracking system 222.The keyboard 266 is configured to receive user input to those graphicaluser interfaces to control one or more functions of the surgical system200.

The processing circuit 260 includes a processor and memory device. Theprocessor can be implemented as a general purpose processor, anapplication specific integrated circuit (ASIC), one or more fieldprogrammable gate arrays (FPGAs), a group of processing components, orother suitable electronic processing components. The memory device(e.g., memory, memory unit, storage device, etc.) is one or more devices(e.g., RAM, ROM, Flash memory, hard disk storage, etc.) for storing dataand/or computer code for completing or facilitating the variousprocesses and functions described in the present application. The memorydevice may be or include volatile memory or non-volatile memory. Thememory device may include database components, object code components,script components, or any other type of information structure forsupporting the various activities and information structures describedin the present application. According to an exemplary embodiment, thememory device is communicably connected to the processor via theprocessing circuit 260 and includes computer code for executing (e.g.,by the processing circuit 260 and/or processor) one or more processesdescribed herein.

More particularly, processing circuit 260 is configured to facilitatethe creation of a preoperative surgical plan prior to the surgicalprocedure. According to some embodiments, the preoperative surgical planis developed utilizing a three-dimensional representation of a patient'sanatomy, also referred to herein as a “virtual bone model.” A “virtualbone model” may include virtual representations of cartilage or othertissue in addition to bone. To obtain the virtual bone model, theprocessing circuit 260 receives imaging data of the patient's anatomy onwhich the surgical procedure is to be performed. The imaging data may becreated using any suitable medical imaging technique to image therelevant anatomical feature, including computed tomography (CT),magnetic resonance imaging (MM), and/or ultrasound. The imaging data isthen segmented (i.e., the regions in the imaging corresponding todifferent anatomical features are distinguished) to obtain the virtualbone model. For example, MM-based scan data of a joint can be segmentedto distinguish bone from surrounding ligaments, cartilage,previously-implanted prosthetic components, and other tissue to obtain athree-dimensional model of the imaged bone.

Alternatively, the virtual bone model may be obtained by selecting athree-dimensional model from a database or library of bone models. Inone embodiment, the user may use input/output device 262 to select anappropriate model. In another embodiment, the processing circuit 260 mayexecute stored instructions to select an appropriate model based onimages or other information provided about the patient. The selectedbone model(s) from the database can then be deformed based on specificpatient characteristics, creating a virtual bone model for use insurgical planning and implementation as described herein.

A preoperative surgical plan can then be created based on the virtualbone model. The surgical plan may be automatically generated by theprocessing circuit 260, input by a user via input/output device 262, orsome combination of the two (e.g., the processing circuit 260 limitssome features of user-created plans, generates a plan that a user canmodify, etc.). In some embodiments, the surgical plan may be generatedand/or modified based on distraction force measurements collectedintraoperatively.

The preoperative surgical plan includes the desired cuts, holes,surfaces, burrs, or other modifications to a patient's anatomy to bemade using the surgical system 200. For example, for a total kneearthroscopy procedure, the preoperative plan may include the cutsnecessary to form, on a femur, a distal surface, a posterior chamfersurface, a posterior surface, an anterior surface, and an anteriorchamfer surface in relative orientations and positions suitable to bemated to corresponding surfaces of the prosthetic to be joined to thefemur during the surgical procedure, as well as cuts necessary to form,on the tibia, surface(s) suitable to mate to the prosthetic to be joinedto the tibia during the surgical procedure. As another example, thepreoperative plan may include the modifications necessary to createholes (e.g., pilot holes 120) in a bone. As another example, in a hiparthroplasty procedure, the surgical plan may include the burr necessaryto form one or more surfaces on the acetabular region of the pelvis toreceive a cup and, in suitable cases, an implant augment. Accordingly,the processing circuit 260 may receive, access, and/or store a model ofthe prosthetic to facilitate the generation of surgical plans. In someembodiments, the processing circuit facilitate intraoperativemodifications to the preoperative plant.

The processing circuit 260 is further configured to generate a controlobject for the robotic device 220 in accordance with the surgical plan.The control object may take various forms according to the various typesof possible robotic devices (e.g., haptic, autonomous). For example, insome embodiments, the control object defines instructions for therobotic device to control the robotic device to move within the controlobject (i.e., to autonomously make one or more cuts of the surgical planguided by feedback from the tracking system 222). In some embodiments,the control object includes a visualization of the surgical plan and therobotic device on the display 264 to facilitate surgical navigation andhelp guide a surgeon to follow the surgical plan (e.g., without activecontrol or force feedback of the robotic device). In embodiments wherethe robotic device 220 is a haptic device, the control object may be ahaptic object as described in the following paragraphs.

In an embodiment where the robotic device 220 is a haptic device, theprocessing circuit 260 is further configured to generate one or morehaptic objects based on the preoperative surgical plan to assist thesurgeon during implementation of the surgical plan by enablingconstraint of the surgical tool 234 during the surgical procedure. Ahaptic object may be formed in one, two, or three dimensions. Forexample, a haptic object can be a line, a plane, or a three-dimensionalvolume. A haptic object may be curved with curved surfaces and/or haveflat surfaces, and can be any shape, for example a funnel shape. Hapticobjects can be created to represent a variety of desired outcomes formovement of the surgical tool 234 during the surgical procedure. One ormore of the boundaries of a three-dimensional haptic object mayrepresent one or more modifications, such as cuts, to be created on thesurface of a bone. A planar haptic object may represent a modification,such as a cut, to be created on the surface of a bone. A curved hapticobject may represent a resulting surface of a bone as modified toreceive a cup implant and/or implant augment. A line haptic object maycorrespond to a pilot hole to be made in a bone to prepare the bone toreceive a screw or other projection.

In an embodiment where the robotic device 220 is a haptic device, theprocessing circuit 260 is further configured to generate a virtual toolrepresentation of the surgical tool 234. The virtual tool includes oneor more haptic interaction points (HIPs), which represent and areassociated with locations on the physical surgical tool 234. In anembodiment in which the surgical tool 234 is a spherical burr (e.g., asshown in FIG. 2), a HIP may represent the center of the spherical burr.Where one HIP is used to virtually represent a surgical tool, the HIPmay be referred to herein as a tool center point (TCP). If the surgicaltool 234 is an irregular shape, for example as for a sagittal saw, thevirtual representation of the sagittal saw may include numerous HIPs.Using multiple HIPs to generate haptic forces (e.g. positive forcefeedback or resistance to movement) on a surgical tool is described inU.S. application Ser. No. 13/339,369, titled “System and Method forProviding Substantially Stable Haptics,” filed Dec. 28, 2011, and herebyincorporated by reference herein in its entirety. In one embodiment ofthe present invention, a virtual tool representing a sagittal sawincludes eleven HIPs. As used herein, references to an “HIP” are deemedto also include references to “one or more HIPs.” As described below,relationships between HIPs and haptic objects enable the surgical system200 to constrain the surgical tool 234.

Prior to performance of the surgical procedure, the patient's anatomy(e.g., femur 206) is registered to the virtual bone model of thepatient's anatomy by any known registration technique. One possibleregistration technique is point-based registration, as described in U.S.Pat. No. 8,010,180, titled “Haptic Guidance System and Method,” grantedAug. 30, 2011, and hereby incorporated by reference herein in itsentirety. Alternatively, registration may be accomplished by 2D/3Dregistration utilizing a hand-held radiographic imaging device, asdescribed in U.S. application Ser. No. 13/562,163, titled “RadiographicImaging Device,” filed Jul. 30, 2012, and hereby incorporated byreference herein in its entirety. Registration also includesregistration of the surgical tool 234 to a virtual tool representationof the surgical tool 234, so that the surgical system 200 can determineand monitor the pose of the surgical tool 234 relative to the patient(i.e., to femur 206). Registration allows for accurate navigation,control, and/or force feedback during the surgical procedure.

The processing circuit 260 is configured to monitor the virtualpositions of the virtual tool representation, the virtual bone model,and the control object (e.g., virtual haptic objects) corresponding tothe real-world positions of the patient's bone (e.g., femur 206), thesurgical tool 234, and one or more lines, planes, or three-dimensionalspaces defined by forces created by robotic device 220. For example, ifthe patient's anatomy moves during the surgical procedure as tracked bythe tracking system 222, the processing circuit 260 correspondinglymoves the virtual bone model. The virtual bone model thereforecorresponds to, or is associated with, the patient's actual (i.e.physical) anatomy and the position and orientation of that anatomy inreal/physical space. Similarly, any haptic objects, control objects, orother planned automated robotic device motions created during surgicalplanning that are linked to cuts, modifications, etc. to be made to thatanatomy also move in correspondence with the patient's anatomy. In someembodiments, the surgical system 200 includes a clamp or brace tosubstantially immobilize the femur 206 to minimize the need to track andprocess motion of the femur 206.

For embodiments where the robotic device 220 is a haptic device, thesurgical system 200 is configured to constrain the surgical tool 234based on relationships between HIPs and haptic objects. That is, whenthe processing circuit 260 uses data supplied by tracking system 222 todetect that a user is manipulating the surgical tool 234 to bring a HIPin virtual contact with a haptic object, the processing circuit 260generates a control signal to the robotic arm 232 to provide hapticfeedback (e.g., a force, a vibration) to the user to communicate aconstraint on the movement of the surgical tool 234. In general, theterm “constrain,” as used herein, is used to describe a tendency torestrict movement. However, the form of constraint imposed on surgicaltool 234 depends on the form of the relevant haptic object. A hapticobject may be formed in any desirable shape or configuration. As notedabove, three exemplary embodiments include a line, plane, orthree-dimensional volume. In one embodiment, the surgical tool 234 isconstrained because a HIP of surgical tool 234 is restricted to movementalong a linear haptic object. In another embodiment, the haptic objectis a three-dimensional volume and the surgical tool 234 may beconstrained by substantially preventing movement of the HIP outside ofthe volume enclosed by the walls of the three-dimensional haptic object.In another embodiment, the surgical tool 234 is constrained because aplanar haptic object substantially prevents movement of the HIP outsideof the plane and outside of the boundaries of the planar haptic object.For example, the processing circuit 260 can establish a planar hapticobject corresponding to a planned planar distal cut needed to create adistal surface on the femur 206 in order to confine the surgical tool234 substantially to the plane needed to carry out the planned distalcut.

For embodiments where the robotic device 220 is an autonomous device,the surgical system 200 is configured to autonomously move and operatethe surgical tool 234 in accordance with the control object. Forexample, the control object may define areas relative to the femur 206for which a cut should be made. In such a case, one or more motors,actuators, and/or other mechanisms of the robotic arm 232 and thesurgical tool 234 are controllable to cause the surgical tool 234 tomove and operate as necessary within the control object to make aplanned cut, for example using tracking data from the tracking system222 to allow for closed-loop control.

Referring now to FIG. 3, a flowchart of a process 300 that can beexecuted by the surgical system 200 of FIG. 2 is shown, according to anexemplary embodiment. Process 300 may be adapted to facilitate varioussurgical procedures, including total and partial joint replacementsurgeries.

At step 302, a surgical plan is obtained. The surgical plan (e.g., acomputer-readable data file) may define a desired outcome of bonemodifications, for example defined based on a desired position ofprosthetic components relative to the patient's anatomy. For example, inthe case of a knee arthroplasty procedure, the surgical plan may provideplanned positions and orientations of the planar surfaces 102-110 andthe pilot holes 120 as shown in FIG. 1. The surgical plan may begenerated based on medical imaging, 3D modeling, surgeon input, etc.

At step 304, one or more control boundaries, such as haptic objects, aredefined based on the surgical plan. The one or more haptic objects maybe one-dimensional (e.g., a line haptic), two dimensional (i.e.,planar), or three dimensional (e.g., cylindrical, funnel-shaped, curved,etc.). The haptic objects may represent planned bone modifications(e.g., a haptic object for each of the planar surfaces 102-110 and eachof the pilot holes 120 shown in FIG. 1), implant components, surgicalapproach trajectories, etc. defined by the surgical plan. The hapticobjects can be oriented and positioned in three-dimensional spacerelative to a tracked position of a patient's anatomy.

At step 306, a pose of a surgical tool is tracked relative to the hapticobject(s), for example by the tracking system 222 described above. Insome embodiments, one point on the surgical tool is tracked. In otherembodiments, (e.g., in the example of FIGS. 4-5) two points on thesurgical tool are tracked, for example a tool center point (TCP) at atip/effective end of the surgical tool and a second interaction point(SIP) positioned along a body or handle portion of the surgical tool. Inother embodiments, three or more points on the surgical tool aretracked. A pose of the surgical tool is ascertained relative to acoordinate system in which the one or more haptic objects are definedand, in some embodiments, in which the pose of one or more anatomicalfeatures of the patient is also tracked.

At step 308, the surgical tool is guided to the haptic object(s). Forexample, the display 264 of the surgical system 200 may display agraphical user interface instructing a user on how (e.g., whichdirection) to move the surgical tool and/or robotic device to bring thesurgical tool to a haptic object. As another example, the surgical toolmay be guided to a haptic object using a collapsing haptic boundary asdescribed in U.S. Pat. No. 9,289,264, the entire disclosure of which isincorporated by reference herein. As another example, the robotic devicemay be controlled to automatically move the surgical tool to a hapticobject.

At step 310, the robotic device is controlled to constrain movement ofthe surgical tool based on the tracked pose of the surgical tool and theposes of one or more haptic objects. The constraining of the surgicaltool may be achieved as described above with reference to FIG. 2.

At step 312, exit of the surgical tool from the haptic object(s) isfacilitated, i.e., to release the constraints of a haptic object. Forexample, in some embodiments, the robotic device is controlled to allowthe surgical tool to exit a haptic object along an axis of the hapticobject. In some embodiments, the surgical tool may be allowed to exitthe haptic object in a pre-determined direction relative to the hapticobject. The surgical tool may thereby be removed from the surgical fieldand the haptic object to facilitate subsequent steps of the surgicalprocedure. Additionally, it should be understood that, in some cases,the process 300 may return to step 308 where the surgical tool is guidedto the same or different haptic object after exiting a haptic object atstep 312.

Process 300 may thereby be executed by the surgical system 200 tofacilitate a surgical procedure. Features of process 300 are shown inFIGS. 4-8 below according to some embodiments, and such features can becombined in various combinations in various embodiments and/or based onsettings selected for a particular procedure. Furthermore, it should beunderstood that the features of FIGS. 4-8 may be provided while omittingsome or all other steps of process 300. All such possibilities arewithin the scope of the present disclosure.

Referring now to FIG. 4, a flowchart of a process 400 for facilitatingsurgical planning and guidance is shown, according to an exemplaryembodiment. The process 400 may be executed by the surgical system 200of FIG. 2, in some embodiments. In some cases, the process 300 isexecuted as part of executing the process 400.

At step 402, segmented pre-operative images and other patient data areobtained, for example by the surgical system 200. For example, segmentedpre-operative CT images or Mill images may be received at the computingsystem 224 from an external server. In some cases, pre-operative imagesof a patient's anatomy are collected using an imaging device andsegmented by a separate computing system and/or with manual user inputto facilitate segmentation. In other embodiments, unsegmentedpre-operative images are received at the computing system 224 and thecomputing system 224 is configured to automatically segment the images.The segmented pre-operative images can show the geometry, shape, size,density, and/or other characteristics of bones of a joint which is to beoperated on in a procedure performed using process 400.

Other patient data can also be obtained at step 402. For example, thecomputing system 224 may receive patient information from an electronicmedical records system. As another example, the computing system 224 mayaccept user input of patient information. The other patient data mayinclude a patient's name, identification number, biographicalinformation (e.g., age, weight, etc.), other health conditions, etc. Insome embodiments, the patient data obtained at step 402 includesinformation specific to the procedure to be performed and the relevantpre-operative diagnosis. For example, the patient data may indicatewhich joint the procedure will be performed on (e.g., right knee, leftknee). The patient data may indicate a diagnosed deformity, for exampleindicating whether a knee joint was diagnosed as having a varusdeformity or a valgus deformity. This or other data that may facilitatethe surgical procedure may be obtained at step 402.

At step 404, a system setup, calibration, and registration workflow isprovided, for example by the surgical system 200. The system setup,calibration, and registration workflows may be configured to prepare thesurgical system 220 for use in facilitating a surgical procedure. Forexample, at step 404, the computing system 224 may operate to providegraphical user interfaces that include instructions for performingsystem setup, calibration, and registrations steps. The computing system224 may also cause the tracking system 222 to collect tracking data andcontrol the robotic device 220 to facilitate system setup, calibration,and/or registration. The computing system 224 may also receivingtracking data from the tracking system 222 and information from thecomputing system 224 and use the received information and data tocalibrate the robotic device 220 and define various geometricrelationships between tracked points (e.g., fiducials, markers), othercomponents of the surgical system 200 (e.g., robotic arm 232, surgicaltool 234, probe), and virtual representations of anatomical features(e.g., virtual bone models).

The system setup workflow provided at step 404 may include guiding therobotic device 220 to a position relative to a surgical table and thepatient which will be suitable for completing an entire surgicalprocedure without repositioning the robotic device 220. For example, thecomputing system 224 may generate and provide a graphical user interfaceconfigured to provide instructions for moving a portable cart of therobotic device 220 into a preferred position. In some embodiments, therobotic device 220 can be tracked to determine whether the roboticdevice 220 is properly positioned. Once the cart is positioned, in someembodiments the robotic device 220 is controlled to automaticallyposition the robotic arm 232 in a pose suitable for initiation ofcalibration and/or registration workflows.

The calibration and registration workflows provided at step 404 mayinclude generating instructions for a user to perform variouscalibration and registration tasks while operating the tracking system222 to generate tracking data. The tracking data can then be used tocalibrate the tracking system 222 and the robotic device 220 and toregister the first fiducial tree 240, second fiducial tree 241, andthird fiducial tree 242 relative to the patient's anatomical features,for example by defining geometric relationships between the fiducialtrees 240-242 and relevant bones of the patient in the example of FIG.2. The registration workflow may include tracking a probe used to touchvarious points on the bones of a joint. In some embodiments, providingthe registration workflow may include providing instructions to couple acheckpoint (e.g., a screw or pin configured to be contacted by a probe)to a bone and tracking a probe as the probe contacts the checkpoint andas the probe is used to paint (i.e., move along, touch many pointsalong) one or more surfaces of the bone. The probe can be moved andtracked in order to collect points in or proximate the joint to beoperated upon as well as at other points on the bone (e.g., at ankle orhip for a knee surgery).

In some embodiments, providing the registration workflow includesgenerating instructions to move the patient's leg to facilitatecollection of relevant tracking data that can be used to identify thelocation of a biomechanical feature, for example a hip center point.Providing the registration workflow can include providing audio orvisual feedback indicating whether the leg was moved in the propermanner to collect sufficient tracking data. Various methods andapproaches for registration and calibration can be used in variousembodiments. Step 404 may include steps performed before or after aninitial surgical incision is made in the patient's skin to initiate thesurgical procedure.

At step 406, an initial assessment workflow is provided, for example bythe surgical system 200. The initial assessment workflow provides aninitial assessment of the joint to be operated upon based on trackedposes of the bones of the joint. For example, the initial assessmentworkflow may include tracking relative positions of a tibia and a femurusing data from the tracking system while providing real-timevisualizations of the tibia and femur via a graphical user interface.The computing system 224 may provide instructions via the graphical userinterface to move the tibia and femur to different relative positions(e.g., different degrees of flexion) and to exert different forces onthe joint (e.g., a varus or valgus force). In some embodiments, theinitial assessment workflow includes determining, by the surgical system220 and based on data from the tracking system 222, whether thepatient's joint has a varus or valgus deformity (which may determine aset of surgeon preferences to be used), and, in some embodiments,determining a magnitude of the deformity. In some embodiments, theinitial assessment workflow may include collecting data relating tonative alignment (coronal and sagittal), native ligament tension, and/ornative gaps between bones of the joint. In some embodiments, the initialassessment workflow may include displaying instructions to exert a forceon the patient's leg to place the joint in a corrected statecorresponding to a desired outcome for a joint arthroplasty procedure,and recording the relative poses of the bones and other relevantmeasurements while the joint is in the corrected state. The initialassessment workflow thereby results in collection of data that may beuseful for the surgical system 200 or a surgeon in later steps ofprocess 400.

At step 408, an implant planning workflow is provided, for example bythe surgical system 200. The implant planning workflow is configured tofacilitate users in planning implant placement relative to the patient'sbones and/or planning bone cuts or other modifications for preparingbones to receive implant components. Step 408 may include generating,for example by the computing system 224, three-dimensional computermodels of the bones of the joint (e.g., a tibia model and a femur model)based on the segmented medical images received at step 402. Step 408 mayalso include obtaining three-dimensional computer models of prostheticcomponents to be implanted at the joint (e.g., a tibial implant modeland a femoral implant model). A graphical user interface can begenerated showing multiple views of the three-dimensional bone modelswith the three-dimensional implant models shown in planned positionsrelative to the three-dimensional bone models. Providing the implantplanning workflow can include enabling the user to adjust the positionand orientation of the implant models relative to the bone models.Planned cuts for preparing the bones to allow the implants to beimplanted at the planned positions can then be automatically based onthe positioning of the implant models relative to the bone models and/orbased on axis or landmark information. In some embodiments, theprocesses herein are performed using landmarks associated with the bone,for example based on information that determines component angles,relative anatomic axes, component resections, hip center, knee center,mechanical axis, epicondyles, flexion to create a component plan, etc.Various combinations of such spatial data may be within the meaning ofbone model as used herein.

The graphical user interface can include data and measurements frompre-operative patient data (e.g., from step 402) and from the initialassessment workflow (step 406) and/or related measurements that wouldresult from the planned implant placement (e.g., spatial relationshipbetween femur and tibia). The planned measurements (e.g., planned gaps,planned varus/valgus angles of limb alignment, etc.) can be calculatedbased in part on data collected via the tracking system 222 in otherphases of process 400, for example from initial assessment in step 406or trialing or tensioning workflows described below with reference tostep 412.

The implant planning workflow may also include providing warnings(alerts, notifications) to users when an implant plan violates variouscriteria. In some cases, the criteria can be predefined, for examplerelated to regulatory or system requirements that are constant for allsurgeons and/or for all patients. In other embodiments, the criteria maybe related to surgeon preferences, such that the criteria for triggeringa warning can be different for different surgeons. In some cases, thecomputing system 224 can prevent the process 400 from moving forward outof the implant planning workflow when one or more of certain criteriaare not met.

The implant planning workflow provided at step 408 thereby results inplanned cuts for preparing a joint to receive prosthetic implantcomponents. In some embodiments, the planned cuts include a planartibial cut and multiple planar femoral cuts, for example as describedabove with reference to FIG. 1. The planned cuts can be defined relativeto the virtual bone models used in the implant planning workflow at step408. Based on registration processes from step 404 which define arelationship between tracked fiducial markers and the virtual bonemodels, the positions and orientations of the planned cuts can also bedefined relative to the tracked fiducial markers, (e.g., in a coordinatesystem used by the tracking system 222). The surgical system 200 isthereby configured to associate the planned cuts output from step 408with corresponding planes or other geometries in real space.

At step 410, a bone preparation workflow is provided, for example by thesurgical system 200. The bone preparation workflow includes guidingexecution of one or more cuts or other bone modifications based on thesurgical plan created at step 408. For example, as explained in detailabove with reference to FIGS. 2-3, the bone preparation workflow mayinclude providing haptic feedback which constrains the surgical tool 234to a plane associated with a planned cut to facilitate use of thesurgical tool 234 to make that planned cut. In other embodiments, thebone preparation workflow can include automatically controlling therobotic device 220 to autonomously make one or more cuts or other bonemodifications to carry out the surgical plan created at step 408. Inother embodiments, the bone preparation workflow comprises causing therobotic device 200 to hold a cutting guide, drill guide, jig, etc. in asubstantially fixed position that allows a separate surgical tool to beused to execute the planned cut while being confined by the cuttingguide, drill guide, jig, etc. The bone preparation workflow can thusinclude control of a robotic device in accordance with the surgicalplan.

The bone preparation workflow at step 410 can also include displayinggraphical user interface elements configured to guide a surgeon incompleting one or more planned cuts. For example, the bone preparationworkflow can include tracking the position of a surgical tool relativeto a plane or other geometry associated with a planned cut and relativeto the bone to be cut. In this example, the bone preparation workflowcan include displaying, in real-time, the relative positions of thesurgical tool, cut plane or other geometry, and bone model. In someembodiments, visual, audio, or haptic warnings can be provided toindicate interruptions to performance of the planned cut, deviation fromthe planned cut, or violation of other criteria relating to the bonepreparation workflow.

In some embodiments, step 410 is provided until all bone cuts planned atstep 408 are complete and the bones are ready to be coupled to theimplant components. In other embodiments, for example as shown in FIG.4, a first iteration of step 410 can include performing only a portionof the planned cuts. For example, in a total knee arthroplastyprocedure, a first iteration of step 410 can include making a tibial cutto provide a planar surface on the tibia without modifying the femur inthe first iteration of step 410.

Following an iteration of the bone preparation workflow at step 410, theprocess 400 can proceed to step 412. At step 412 a mid-resectiontensioning workflow or a trialing workflow is provided, for example bythe surgical system 200. The mid-resection tensioning workflow isprovided when less than all of the bone resection has been completed.The trialing workflow is provided when all resections have been madeand/or bones are otherwise prepared to be temporarily coupled to trialimplants. The mid-resection tensioning workflow and the trialingworkflow at step 412 provide for collection of intraoperative datarelating to relative positions of bones of the joint using the trackingsystem 222 including performing gap measurements or other tensioningprocedures that can facilitate soft tissue balancing and/or adjustmentsto the surgical plan.

For example, step 412 may include displaying instructions to a user tomove the joint through a range of motion, for example from flexion toextension, while the tracking system 222 tracks the bones. In someembodiments, gap distances between bones are determined from datacollected by the tracking system 222 as a surgeon places the joint inboth flexion and extension. In some embodiments, soft tissue tension ordistraction forces are measured. Because one or more bone resectionshave been made before step 412 and soft tissue has been affected by theprocedure, the mechanics of the joint may be different than during theinitial assessment workflow of step 402 and relative to when thepre-operative imaging was performed. Accordingly, providing forintra-operative measurements in step 412 can provide information to asurgeon and to the surgical system 200 that was not availablepre-operatively and which can be used to help fine tune the surgicalplan.

From step 412, the process 400 returns to step 408 to provide theimplant planning workflow again, now augmented with data collectedduring a mid-resection or trialing workflow at step 412. For example,planned gaps between implants can be calculated based on theintraoperative measurements collected at step 414, the planned positionof a tibial implant relative to a tibia, and the planned position of afemoral implant relative to a femur. The planned gap values can then bedisplayed in an implant planning interface during step 408 to allow asurgeon to adjust the planned implant positions based on the calculatedgap values. In various embodiments, a second iteration of step 408 toprovide the implant planning workflow incorporates various data fromstep 412 in order to facilitate a surgeon in modifying and fine-tuningthe surgical plan intraoperatively.

Steps 408, 410, and 412 can be performed multiple times to provide forintra-operative updates to the surgical plan based on intraoperativemeasurements collected between bone resections. For example, in somecases, a first iteration of steps 408, 410, and 412 includes planning atibial cut in step 408, executing the planned tibial cut in step 410,and providing a mid-resection tensioning workflow in step 414. In thisexample, a second iteration of steps 408, 410, and 412 can includeplanning femoral cuts using data collected in the mid-resectiontensioning workflow in step 408, executing the femoral cuts in step 410,and providing a trialing workflow in step 412. Providing the trialingworkflow can include displaying instructions relating to placing trialimplants on the prepared bone surfaces, and, in some embodiments,verifying that the trial implants are positioned in planned positionsusing the tracking system 222. Tracking data can be collected in atrialing workflow in step 412 relating to whether the trial implants areplaced in acceptable positions or whether further adjustments to thesurgical plan are needed by cycling back to step 408 and making furtherbone modifications in another iteration of step 410.

In some embodiments, executing process 400 can include providing userswith options to jump between steps of the process 400 to enter a desiredworkflow. For example, a user can be allowed to switch between implantplanning and bone preparation on demand. In other embodiments, executingprocess 400 can include ensuring that a particular sequence of steps ofprocess 400 are followed. In various embodiments, any number ofiterations of the various steps can be performed until a surgeon issatisfied that the bones have been properly prepared to receive implantcomponents in clinically-appropriate positions.

As shown in FIG. 4, the process 400 includes step 414 where implantationof prosthetic components is facilitated. Once the bones have beenprepared via step 410, the prosthetic components can be implanted. Insome embodiments, step 414 is executed by the surgical system 200 byremoving the robotic arm 232 from the surgical field and otherwisegetting out of the way to allow a surgeon to fix the prostheticcomponents onto the bones without further assistance from the surgicalsystem 200. In some embodiments, step 414 includes displayinginstructions and/or navigational information that supports a surgeon inplacing prosthetic components in the planned positions. In yet otherembodiments, step 414 includes controlling the robotic arm 232 to placeone or more prosthetic components in planned positions (e.g., holding aprosthetic component in the planned position while cement cures, whilescrews are inserted, constraining an impaction device to plannedtrajectory). Process 400 can thereby result in prosthetic componentsbeing affixed to modified bones according to an intra-operativelyupdated surgical plan.

Referring generally to the FIGURES, embodiments described herein providesystems and methods to check and verify an initial native deformitydetermination made by a user (e.g., a physician or other medicalprofessional) during or prior to the initial assessment workflow. Insome embodiments, the user manipulates the leg of the patient todetermine a native deformity as an initial step in surgical planning.The manipulation may include moving the tibia 208 and/or the femur 206to a position of maximum extension to determine whether a varus orvalgus deformity exists. The user may determine a value of the varus orvalgus deformity in terms of an angle between the tibia 208 and thefemur 206, and the value may be provided to the computing system 224.Determining the native deformity accurately is important, as the variousmodifications to the femur 206 and/or tibia 208 are made based oncorrecting the native deformity. Accordingly, accurately measuring thenative deformity may be critical to a successful surgical outcome.

Such accurate measurements may be determined by the computing system 224and the tracking system 222. In some embodiments, after the user hasdetermined an initial native deformity, the user is instructed by thecomputing system 224 to manipulate the tibia 208 and femur 206 such thatthe computing system can detect the native deformity based on thepositions of the first fiducial tree 240 (e.g., marker, reflector, etc.)(which provides the position of the tibia 208) and the second fiducialtree 241 (which provides the position of the femur 206). The computingsystem 224 detects the native deformity by tracking the positions of thefirst fiducial tree 240 and the second fiducial tree 241 and comparesthe detected native deformity to the user-input native deformity. Insome embodiments, the computing system 224 determines whether the valueof the user-input native deformity is within an acceptable range of thedetected native deformity. If the computing system 224 determines thatthe value of the user-input native deformity is within the acceptablerange of the detected native deformity, the surgical preparationcontinues. In some scenarios, if the computing system 224 determinesthat the value of the user-input native deformity is not within theacceptable range of the detected native deformity, a warning isgenerated and the user is notified. In some embodiments, the user mustacknowledge the warning and can then 1) accept the detected nativedeformity as the accepted native deformity for use in future stages ofthe workflow, 2) measure the native deformity again to generate anupdated user-input native deformity, or 3) reposition one or both of thefirst fiducial tree 240 and the second fiducial tree 241 if the userdetermines that the initial placement was incorrect. This process maycontinue until either 1) the user accepts the detected native deformityor 2) the user generates an updated user-input native deformity that iswithin the acceptable range of the detected native deformity. Theprocess can also include allowing the user to move the tibia relative tothe femur to correct the deformity while collected data.

Embodiments described herein may result in a more accurate determinationof a native deformity as compared to surgical procedures in which thenative deformity is not determined as described above, thereby resultingin fewer complications and better surgical outcomes.

Referring now to FIG. 5, an illustration of a graphical user interface500 showing a relationship between a virtual femur 502 and a virtualtibia 504 is shown, according to an exemplary embodiment. The graphicaluser interface 500 is shown on the display 264 and provides the userwith information received, calculated, determined, or otherwiseprocessed by the processing circuit 260. The virtual femur 502 is avirtual representation of the femur 206 and thus comprises substantiallythe same size and substantially the same shape as the femur 206. Thevirtual tibia 504 is a virtual representation of the tibia 208 and thuscomprises substantially the same size and substantially the same shapeas the tibia 208. As shown, the virtual femur 502 and the virtual tibia504 are in extension (e.g., a straightened relationship) to determinethe native deformity.

The graphical user interface 500 further includes a femoral centerline508 and a tibial centerline 506. The femoral centerline 508 extends froma center of a head of the virtual femur 502 (not shown) toward a centralportion of the virtual femur 502 between a virtual lateral condyle and avirtual medial condyle. The tibial centerline 506 extends from a centerof a tibial plateau of the virtual tibia 504 and through a central axisof a shaft (not shown) of the virtual tibia 504. As shown in FIG. 5, thefemoral centerline 508 is offset from the tibial centerline 506, therebycreating an offset angle 510. The value of the offset angle indicateswhether a varus or valgus native deformity exists. For example, and asshown in FIG. 5, the virtual femur 502 is angled laterally to thevirtual tibia 504, thereby creating the offset angle 510. As shown onthe graphical user interface 500, the offset angle 510 is four degrees,indicating that the computing system 224 detected a four degree varusnative deformity. In embodiments where a valgus deformity exists, theoffset angle 510 would be negative (e.g., the virtual femur 502 would beangled medially to the virtual tibia 504). Though determining the nativedeformity is described above as comparing the femoral centerline 508 andthe tibial centerline 506, one of skill would understand that the nativedeformity may be determined using additional and/or other anatomicallandmarks.

In an example embodiment, the user may have previously determined thatthe native deformity is four degrees varus (e.g., while manuallymanipulating the femur 206 and the tibia 208, in a pre-surgicalassessment of the patient) and provided that information to thecomputing system 224 (e.g., from a patient file, from an electronicmedical records system). In some embodiments, the user-input nativedeformity is provided for reference on a deformity table 512 of thegraphical user interface 500. In some embodiments, the detected nativedeformity is also shown on the deformity table 512 of the graphical userinterface 500, for example as shown in FIG. 5. In this example scenario,upon the determination by the computing system 224 that the detectednative deformity is four degrees, the computing system 224 determinesthat the user-input native deformity and the detected native deformityare a perfect match. Because the two values match, the native deformityis verified and the computing system 224 continues preparation forsurgery. In other scenarios, if a disagreement is determined between thedetected native deformity and the user-input native deformity (e.g., adifference greater than a threshold), an alert may be generated, forexample as described in detail below with reference to later figures.

In other embodiments, the computing system 224 compares the detectednative deformity to a type of native deformity selected by the user(e.g., a user-selected deformity type). For example, when initiallyassessing a joint of a patient, the user may only be required to selectwhether the native deformity is varus or valgus and not be required toprovide a numerical value corresponding to the deformity. In suchembodiments, the computing system compares the detected native deformityto the user-selected native deformity to confirm that the user-selectednative deformity and the detected native deformity comprise the sametype of deformity (e.g., both indicate that the native deformity is avalgus deformity). If the comparison shows that both the user-selectednative deformity and the detected native deformity indicate the sametype of native deformity, the surgical planning will continue. If, onthe other hand, the comparison shows that the user-selected deformityand the detected native deformity are different, the computing system224 may notify the user via the graphical user interface 500 of thedifference, and prompt the user to re-evaluate the user-selecteddeformity.

In some embodiments, the deformity table 512 also includes an indicationof the native deformity and an indication of a corrected deformity. Thecorrected deformity refers to a position of the joint (e.g.,varus/valgus, extension, etc.) where the femoral centerline 508 and thetibial centerline 506 are aligned to an extent possible throughapplication of an external corrective force on the joint. The deformitytable 512 also includes an extension widget (flexion widget) 514. Theextension widget 514 is configured to provide a visual representation ofthe degree of flexion/extension of the leg of the patient whendetermining the native deformity. The extension widget 514 is shown toinclude a zero line 516 and an indicator 518. The zero line 516 providesa reference that indicates to the user where the joint is in neitherflexion (e.g., bent posteriorly) nor extension (e.g., bent anteriorly)(i.e., at zero degrees of flexion and at zero degrees extension). Theindicator 518 shows the user how much the joint is bent relative to thezero line 516. For example, the indicator 518 moving away from the zeroline 516 in the direction of the virtual femur 502 indicates that thejoint is increasing in flexion angle. The indicator moving away from thezero line 516 in the direction of the virtual tibia 508 indicates thatthe joint decreasing the flexion angle. The magnitude of flexion orextension is shown at the top of the flexion widget 514 (e.g., the jointshown in FIG. 5 is in extension by two degrees).

The corrected deformity is obtained by the user manipulating the femur206 and the tibia 208 of the patient until the varus/valgus indicationmoves to approximately zero to some other physically attainable valuethat a caregiver regards as a corrected (e.g., proper, healthy, desired)alignment. Once the user has placed the joint in a position of correcteddeformity, the computing system 224 includes the corrected deformityand, optionally, the corrected flexion/extension on the graphical userinterface 500. In some embodiments, if the corrected deformity isgreater than an upper limit (e.g., the joint is not sufficientlymanipulated toward a zero varus/valgus angle such that the correctedvarus/valgus angle is above the upper limit), then the system maygenerate a notification in response and provide the notification via thegraphical user interface 500 (e.g., by highlighting the correcteddeformity angle, placing a box around the corrected deformity angle, orotherwise drawing the attention of the user to the corrected deformityangle). In some instances, the user cannot manipulate the femur 206 andthe tibia 208 to achieve a corrected deformity (e.g., in some instancesthe joint of the patient is so far away from a corrected deformity thatit is not possible to force the joint into a sufficiently-correctedangle). In such embodiments, the user may be notified via the graphicaluser interface 500 that switching to a mid-resection workflow (e.g.,reassessing the corrected deformity later in the procedure) may providemore useful results.

Referring now to FIG. 6, another illustration of the graphical userinterface 500 of FIG. 5 showing another relationship between the virtualfemur 502 and the virtual tibia 504 is shown, according to an exemplaryembodiment. As shown in FIG. 6, the femoral centerline 508 and thetibial centerline 506 create an offset angle 610 of 5.5 degrees,indicating that the computing system 224 is currently reading a 5.5degree varus deformity during live tracking. The deformity table 512indicates that the captured native deformity is four degrees.

Referring now to FIG. 7, yet another illustration of the graphical userinterface 500 of FIG. 5 showing another relationship between the virtualfemur 502 and the virtual tibia 504 is shown, according to an exemplaryembodiment. As shown in FIG. 7, the femoral centerline 508 and thetibial centerline 506 create an offset angle 710 of 7.0 degrees,indicating that the computing system 224 is detecting a 7.0 degree varusdeformity as a live-tracked value. The deformity table 512 indicatesthat the captured native deformity is four degrees. The computing systemcompares the user-input native deformity to the detected nativedeformity and determines that there is a difference of three degrees. Asdescribed above in the example embodiment discussed in FIG. 6, thethreshold tolerance for the difference between the user-input nativedeformity and the detected deformity may be two degrees. The computingsystem 224 determines that the difference between the user-input nativedeformity and the detected native deformity is not within the threshold.It is important for the native deformity to be properly characterized,as the femur 206 is shaped during the surgical procedure to at leastpartially correct or otherwise account for the native deformity.Accordingly, if the native deformity is mischaracterized during surgicalpreparation, the outcome of the surgical procedure may be less thanideal. Accordingly, the computing system 224 determines that thesurgical preparation should not continue unless the situation isremedied.

To notify the user that a discrepancy exists between the user-inputnative deformity and the detected native deformity, the computing system224 causes a warning box 712 to be displayed on the graphical userinterface 500. As shown, the warning box displays a visual alert thatstates “the user-input native deformity and the detected nativedeformity are different,” however one of skill in the art wouldunderstand that the words used in the warning may be altered as long asthe user is warned of the discrepancy. In some embodiments, the warningmay be in the form of an audio warning (e.g., a recorded messagenotifying the user of the discrepancy). In some embodiments, the warningmay include flashing lights on the graphical user interface 500. In someembodiments, the warning may be a combination of visual and audiowarnings.

In some embodiments, the computing system 224 may then prompt the userto check for various errors. Those errors include, but are not limitedto, user errors in determining the user-input native deformity, usererrors in recording the user-input native deformity, errors in couplingone or both of the first fiducial tree 240 and the second fiducial tree241 to the tibia 208 and the femur 206, errors in registration, etc.After the discrepancy is remedied and the difference between theuser-input native deformity and the detected native deformity is withinthe threshold, preparation for the surgical procedure can continue.

Referring now to FIG. 8, a flowchart 800 of a process to determine anative deformity of a joint is shown, according to an exemplaryembodiment. The steps described in reference to the flowchart 800 can beexecuted by, for example, the computing system 224.

At step 802, a user-input native deformity of a joint is received. Asdescribed with reference FIGS. 5-7, a user determines the nativedeformity of the joint between the tibia 208 and the femur 206 byphysically manipulating the tibia 208 and the femur 206 relative to eachother. After determining the native deformity of the joint, the userprovides the deformity of the joint to the computing system 224 as theuser-input native deformity. The user-input native deformity may beascertained at the time of the surgical procedure or may be sourced froma previous assessment of the patient (e.g., an earlier appointment withthe patient).

At step 804, a position of a first marker is tracked. For example, andas described with reference to FIGS. 2 and 5-7, the tracking system 222tracks a position of the first fiducial tree 240 (or other type oftrackable element or marker in various embodiments) and provides thetracking information to the computing system 224 to determine a positionof the tibia 208 as the user moves the tibia 208 relative to the femur206.

At step 806, a position of a second marker is tracked. For example, andas described with reference to FIGS. 2 and 5-7, the tracking system 222tracks a position of the second fiducial tree 241 (or other type oftrackable element or marker in various embodiments) and provides thetracking information to the computing system 224 to determine a positionof the femur 206 as the user moves the femur 206 relative to the tibia208.

At step 808, a native deformity of the joint is detected. For example,the computing system 224 processes data received by the tracking system222 regarding the position of the first fiducial tree 240 and theposition of the second fiducial tree 241 as a user manipulates the femur206 and the tibia 208. Based on the position data received by thecomputing system 224, the computing system 224 determines a detectednative deformity of the joint.

At step 810, a determination is made as to whether a difference betweenthe user-input native deformity and the detected native deformity isgreater than a threshold value. For example, the threshold value may bebased on a varus and/or valgus angle where the difference between thevalue of the user-input native deformity (e.g., user-input varus orvalgus angle) and the value of the detected native deformity (e.g.,detected varus or valgus angle) is compared by the computing system 224.If the computing system 224 finds that the difference between theuser-input native deformity and the detected native deformity is lessthan the threshold value (NO at step 810), then an implant planningworkflow is provided (e.g., step 408 of FIG. 4).

If the computing system 224 finds that the difference between theuser-input native deformity and the detected native deformity is greaterthan the threshold value (YES at step 810), then an alert is generatedat step 812. For example, an alert may be displayed on the graphicaluser interface 500 to notify the user that the difference between theuser-input native deformity and the detected native deformity is greaterthan the threshold value. In other embodiments, the alert may be anaudible alert (e.g., an alarm, a voice, etc.) that notifies the userthat the difference between the user-input native deformity and thedetected native deformity is greater than the threshold value. Theaudible alert may be provided by an audible device (e.g., speakers,etc.) coupled with the computing system 224. In some embodiments, thealert may include both visual and audible alerts to notify the user ofthe discrepancy. The alert may also include a prompt to correct anyerrors that may have led to the discrepancy such that the discrepancycan be corrected before continuing with surgical preparation.

The term “coupled” and variations thereof, as used herein, means thejoining of two members directly or indirectly to one another. Suchjoining may be stationary (e.g., permanent or fixed) or moveable (e.g.,removable or releasable). Such joining may be achieved with the twomembers coupled directly to each other, with the two members coupled toeach other using a separate intervening member and any additionalintermediate members coupled with one another, or with the two memberscoupled to each other using an intervening member that is integrallyformed as a single unitary body with one of the two members. If“coupled” or variations thereof are modified by an additional term(e.g., directly coupled), the generic definition of “coupled” providedabove is modified by the plain language meaning of the additional term(e.g., “directly coupled” means the joining of two members without anyseparate intervening member), resulting in a narrower definition thanthe generic definition of “coupled” provided above. Such coupling may bemechanical, electrical, or fluidic.

References herein to the positions of elements (e.g., “top,” “bottom,”“above,” “below”) are merely used to describe the orientation of variouselements in the FIGURES. It should be noted that the orientation ofvarious elements may differ according to other exemplary embodiments,and that such variations are intended to be encompassed by the presentdisclosure.

The hardware and data processing components used to implement thevarious processes, operations, illustrative logics, logical blocks,modules and circuits described in connection with the embodimentsdisclosed herein may be implemented or performed with a general purposesingle- or multi-chip processor, a digital signal processor (DSP), anapplication specific integrated circuit (ASIC), a field programmablegate array (FPGA), or other programmable logic device, discrete gate ortransistor logic, discrete hardware components, or any combinationthereof designed to perform the functions described herein. A generalpurpose processor may be a microprocessor, or, any conventionalprocessor, controller, microcontroller, or state machine. A processoralso may be implemented as a combination of computing devices, such as acombination of a DSP and a microprocessor, a plurality ofmicroprocessors, one or more microprocessors in conjunction with a DSPcore, or any other such configuration. In some embodiments, particularprocesses and methods may be performed by circuitry that is specific toa given function. The memory (e.g., memory, memory unit, storage device)may include one or more devices (e.g., RAM, ROM, Flash memory, hard diskstorage) for storing data and/or computer code for completing orfacilitating the various processes, layers and modules described in thepresent disclosure. The memory may be or include volatile memory ornon-volatile memory, and may include database components, object codecomponents, script components, or any other type of informationstructure for supporting the various activities and informationstructures described in the present disclosure. According to anexemplary embodiment, the memory is communicably connected to theprocessor via a processing circuit and includes computer code forexecuting (e.g., by the processing circuit or the processor) the one ormore processes described herein.

The present disclosure contemplates methods, systems and programproducts on any machine-readable media for accomplishing variousoperations. The embodiments of the present disclosure may be implementedusing existing computer processors, or by a special purpose computerprocessor for an appropriate system, incorporated for this or anotherpurpose, or by a hardwired system. Embodiments within the scope of thepresent disclosure include program products comprising machine-readablemedia for carrying or having machine-executable instructions or datastructures stored thereon. Such machine-readable media can be anyavailable media that can be accessed by a general purpose or specialpurpose computer or other machine with a processor. By way of example,such machine-readable media can comprise RAM, ROM, EPROM, EEPROM, orother optical disk storage, magnetic disk storage or other magneticstorage devices, or any other medium which can be used to carry or storedesired program code in the form of machine-executable instructions ordata structures and which can be accessed by a general purpose orspecial purpose computer or other machine with a processor. Combinationsof the above are also included within the scope of machine-readablemedia. Machine-executable instructions include, for example,instructions and data which cause a general purpose computer, specialpurpose computer, or special purpose processing machines to perform acertain function or group of functions.

Although the figures and description may illustrate a specific order ofmethod steps, the order of such steps may differ from what is depictedand described, unless specified differently above. Also, two or moresteps may be performed concurrently or with partial concurrence, unlessspecified differently above. Such variation may depend, for example, onthe software and hardware systems chosen and on designer choice. Allsuch variations are within the scope of the disclosure. Likewise,software implementations of the described methods could be accomplishedwith standard programming techniques with rule-based logic and otherlogic to accomplish the various connection steps, processing steps,comparison steps, and decision steps.

What is claimed is:
 1. A surgical system, comprising: a first trackablemarker configured to be coupled to a first bone of a joint; a secondtrackable marker configured to be coupled to a second bone of the joint;a tracking system configured to track a position of the first trackablemarker and a position of the second trackable marker; and a controllerconfigured to: receive, via a user interface, an input from a userspecifying a user-input native deformity of the joint; determine, basedon the position of the first trackable marker and the position of thesecond trackable marker, a detected native deformity of the joint;compare the detected native deformity of the joint to the user-inputnative deformity of the joint; and generate an alert in response to adisagreement between the detective native deformity of the joint and theuser-input native deformity of the joint.
 2. The surgical system ofclaim 1, wherein the controller is configured to generate the alert whenthe detected native deformity differs from the user-input nativedeformity by more than a threshold amount.
 3. The surgical system ofclaim 1, wherein the controller is further configured to: prompt theuser to take an action to correct an error that caused the disagreementbetween the detected native deformity and the user-input nativedeformity; receive an updated user-input native deformity; and comparethe updated user-input native deformity to the detected nativedeformity.
 4. The surgical system of claim 1, wherein the controller isfurther configured to: prompt the user to take an action to correct anerror that caused the disagreement between the detected native deformityand the user-input native deformity; receive an updated detected nativedeformity; and compare the updated detected native deformity to theuser-input native deformity.
 5. The surgical system of claim 1, whereinthe alert comprises one or more of a visual alert displayed on agraphical user interface and an audible alert provided through anaudible device.
 6. The surgical system of claim 1, further comprising agraphical user interface configured to display the detected nativedeformity and show a virtual representation of the first bone and avirtual representation of the second bone.
 7. The surgical system ofclaim 6, wherein the graphical user interface is further configured todisplay the detected native deformity based on anatomical landmarks ofthe virtual representation of the first bone and the virtualrepresentation of the second bone.
 8. A method of providing surgicalnavigation, comprising: tracking a position of a first trackable markercoupled to a first bone of a joint; tracking a position of a secondtrackable marker coupled to a second bone of the joint; receiving aninput from a user specifying a user-input native deformity of the joint;determining, based on the position of the first trackable marker and theposition of the second trackable marker, a detected native deformity ofthe joint; and comparing the detected native deformity of the joint tothe user-input native deformity of the joint; generating an alert inresponse to a disagreement between the detected native deformity of thejoint and the user-input native deformity of the joint.
 9. The method ofclaim 8, wherein comparing the detected native deformity to theuser-input native deformity comprises determining whether the detectednative deformity differs from the user-input native deformity by morethan a threshold amount.
 10. The method of claim 8, further comprising:prompting the user to take an action to correct an error that caused thedisagreement between the detected native deformity and the user-inputnative deformity; receiving an updated user-input native deformity; andcomparing the updated user-input native deformity to the detected nativedeformity.
 11. The method of claim 8, further comprising: prompting theuser to take an action to correct an error that caused the disagreementbetween the detected native deformity and the user-input nativedeformity; determining an updated detected native deformity; andcomparing the updated detected native deformity to the user-input nativedeformity.
 12. The method of claim 8, wherein the alert comprises one ormore of a visual alert displayed on a graphical user interface and anaudible alert provided through an audible device.
 13. The method ofclaim 8, further comprising displaying the detected native deformity ona graphical user interface by showing a virtual representation of thefirst bone and a virtual representation of the second bone.
 14. Themethod of claim 13, further comprising displaying the detected nativedeformity on the graphical user interface by showing anatomicallandmarks of the virtual representation of the first bone and thevirtual representation of the second bone.
 15. A navigation system,comprising: a computer programmed to: track a position of a firsttrackable marker coupled to a first bone of a joint using data from atracking system; track a position of a second trackable marker coupledto a second bone of the joint using data from the tracking system;receive an input from a user specifying a user-input native deformity ofthe joint; determine, based on the position of the first trackablemarker and the position of the second trackable marker, a detectednative deformity of the joint; and compare the detected native deformityof the joint to the user-input native deformity of the joint.
 16. Thenavigation system of claim 15, wherein the computer is furtherprogrammed to generate an alert in response to determining adisagreement between the detected native deformity and the user-inputnative deformity.
 17. The navigation system of claim 16, wherein thecomputer is further programmed to: prompt the user to take an action tocorrect an error that caused the disagreement between the detectednative deformity and the user-input native deformity; receive an updateduser-input native deformity; and compare the updated user-input nativedeformity to the detected native deformity.
 18. The navigation system ofclaim 16, wherein the computer is further programmed to: prompt the userto take an action to correct an error that caused the disagreementbetween the detected native deformity and the user-input nativedeformity; determine an updated detected native deformity using datafrom the tracking system; and compare the updated detected nativedeformity to the user-input native deformity.
 19. The navigation systemof claim 15, wherein the computer is further programmed to cause thedetected native deformity to be displayed on a graphical user interfaceand show a virtual representation of the first bone and a virtualrepresentation of the second bone.
 20. The navigation system of claim19, wherein the computer is further programmed to cause the detectednative deformity to be displayed on the graphical user interface basedon anatomical landmarks of the virtual representation of the first boneand the virtual representation of the second bone.